Coexistence of Multiple Metastatic Lesions Showing Various Grades of Differentiation in a Single Patient with Neuroendocrine Tumor of Lung as Primary: A Combined Modality Approach of (68)Ga-DOTANOC Positron Emission Tomography/Computed Tomography and (18)F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging

Neuroendocrine tumors (NETs) of gastrointestinal (GI) tract and lungs are a rare variety of tumors but given their indolent nature are quite prevalent. These tumors are mostly malignant in nature and are often diagnosed in advanced stages. GI tracts are the most common sites of NETs followed by lungs, thymus, and other less common sites being ovaries, testis, and hepatobiliary system. Nuclear medicine imaging modalities include (68)Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) which is sensitive for low-grade NETs and (18)F-fluorodeoxyglucose (FDG) PET/CT which is more valuable for high-grade NETs. However, intermediate-grade NETs are equally sensitive to both (68)Ga-DOTANOC PET/CT and 18F-FDG PET/CT.